• Journal of the Korea Concrete Institute
• /
• v.17 no.1 s.85
• /
• pp.69-76
• /
• 2005

In this study, the high qualify recycled fine aggregate manufacturing system by the drying specific gravity separation method was evaluated. For the evaluation of the performance of the recycled aggregate, the engineering properties and durability of recycled aggregate has been tested. From the test results, the quality of recycled fing aggregates was improved by high quality recycled fine aggregate manufacturing system and satisfied with the quality standards of KS and JASS 5. Also, compressive and tensile strengths of recycled concrete show no critical difference caused by recycled fine aggregate replacement ratio. However, durability such as carbonation depth chloride ion penetration depth and drying shrinkage shows more deterioration than the concrete without recycled fine aggregate

• Journal of the Korea Concrete Institute
• /
• v.13 no.5
• /
• pp.438-446
• /
• 2001

Recently, porous concrete has been used for the purpose of decreasing the load of earth environment. It consists solely of cement, water and uniform-sized coarse aggregate. And its fundamental properties will be considerably affected by the physical properties of aggregate because the aggregate occupies for the most part in its mix proportion. For such a reason, this study was carried out to investigate the influence of the sizes and kinds of aggregate for the fundamental properties of porous concrete. It showed that the fundamental properties of porous concrete were the similar value in all sizes of aggregate except in the case of using the 2.5∼5㎜ aggregate and were varied according to the kinds of aggregate. In particular, compressive strength of porous concrete using 2.5∼5㎜ aggregate was more higher than that using other aggregate, and its void ratio and coefficient of permeability was lower. And the maintenance capacity of permeability of porous concrete was varied by the sizes and the kinds of aggregate. In particular, it was greatly decreased in case of using the 2.5∼5㎜ aggregate. And unlike dynamic modulus of elasticity of ordinary concrete, that of porous concrete was very high value in early ages and was slowly increased after that time.

• Journal of the Korea Concrete Institute
• /
• v.20 no.5
• /
• pp.661-668
• /
• 2008

It is necessary to develop a new technology for effectively reducing hydration heat and controlling thermal cracking caused increasing construction of large size massive concrete structures such as mat foundation of high-rise building, grandiose bridge, and LNG tank. Therefor, to develop a new technology for reducing hydration heat of large size massive concrete in this study, after developing the latent heat binder for controling hydration heat of concrete by application of latent heat material, it was investigated basic properties and durability such as slump, air content and compressive strength, shrinkage properties, permeability, freezing and thawing resistance, corrosion, and hydration heat generation properties of concrete using latent heat binder. As a test result, it was confirmed that latent heat binder was not affected adversely the basic property and durability of concrete, and was advanced on the reduction of hydration heat and control of thermal crack. It is expected to be applied as the excellent technology on the management of hydration heat and thermal crack in large size mass concrete structures.

• The Journal of the Korean life insurance medical association
• /
• v.20
• /
• pp.53-61
• /
• 2001

1999년 1월-1999년 10월까지 당사에서 1급장해로 인해 보험금이 지급된 1,297 건을 대상으로 하여 성별 & 연령대별 분포, 1급장해 각 항의 원인별 분포, 다빈도원인별 1급장해 각 항의 분포상황등을 중심으로 조사하였다. 1. 1급장해지불건들의 성별분포를 보면 남자가 여자보다1.7배 많았다. 연령대별로는 30대가 29.3%로 가장 높았고 다음으로 40대 23.7%, 20대 18.6%, 10세미만 17.6% 순서 였다. 2. 1급장해 각항별 점유율을 보면 1급3항이 56.9%로 가장 높았고 다음으로 1급4항이 16.0%로 많았다. 3. 1급장해의 원인별 분포를 보면 '교통사고' 및 '교통사고외의 외상'이 597건(40.6%)으로 가장 많이 차지하였고 다음으로 '기타질병' 256건(19.7%) '뇌혈관사고' 245건(18.7%), '만성신부전' 194건(15.0 %), 그리고 '악성종양' 36건(2.8%)의 순서였다. 1) 1급 1항 : 두눈의 시력을 완전영구히 잃었을 때 원인중 가장 많은 것은 '기타질병' 74건(64%)이었고 다음으로는 '당뇨병' 17건(14.9) 그리고 '교통사고'의 순서였다. '기타질병'에 해당하는 병중에서 눈의 질환들을 더 분류하여 볼 때 '맥락막 및 망막의 장애'가 25건(35.7%)으로 가장 많았고 다음으로 '시신경 및 시각경로의 장애' 20건(28.6%) 그리고 '수정체의 장애'의 순서였다. 2) 1급 3항 : 중추신경계, 정신에 뚜렷한 장해를 남겨서 평생토록 항상 간호를 받아야 할 때 원인으로는 '교통사고' 245건(33.2%)이 가장 많았고 다음으로 '뇌혈관사고' 215건(29.1%) 그리고 '교통사고외의 외상'의 순서였다. 뇌혈관사고 215건에 대해서 원인별분포를 보면 '뇌내출혈'이 131건(60.9%)로 '뇌경색 ' 57건(26.5%)에 비해 2.3배 정도 많았다. 3) 1급 4항 : 흉복부장기에 뚜렷한 장해를 남겨서 평생토록 항상 간호를 받아야 할 때 원인으로는 '만성신부전'이 215건(86.5%)으로 가장 많이 차지하고 있었고 다음으로 '기타질병' 14건(6.7%)의 순서였다. 4) 1급 6항 : 두다리의 발목이상을 잃었거나 완전영구히 사용하지 못하게 되었을 때 원인으로는 '교통사고' 41건(41.0%)로 가장 많았고 다음으로 '교통사고외의 외상' 32건 (32.0%) 그리고 다음으로 '근골격계, 결합조직의 질환' 순서였다. 4. 장해원인별 1급장해 각 항의 분포를 보면 '만성신부전'은 1급 4항, '악성종양'은 1급 3항과 1급2항 그리고 1항의 장해를 주로 일으키고 '당뇨병'은 1급 1항, '뇌혈관사고'는 1급3항과 1급2항의 장해를 주로 일으켰다. 한편 '교통사고'나 '교통사고외의 외상'은 주로 1급3항과 1급6항의 장해를 주로 일으켰다.

• Korean Journal of Remote Sensing
• /
• v.27 no.2
• /
• pp.75-87
• /
• 2011

This paper presents a method for region-based building extraction from high resolution satellite images(HRSI) using integrated information of spectral and color invariant features without user intervention such as selecting training data sets. The purpose of this study is also to evaluate the effectiveness of the proposed method by applying to IKONOS and QuickBird images. Firstly, the image is segmented by the MSRG method. The vegetation and shadow regions are automatically detected and masked to facilitate the building extraction. Secondly, the region merging is performed for the masked image, which the integrated information of the spectral and color invariant features is used. Finally, the building regions are extracted using the shape feature for the merged regions. The boundaries of the extracted buildings are simplified using the generalization techniques to improve the completeness of the building extraction. The experimental results showed more than 80% accuracy for two study areas and the visually satisfactory results obtained. In conclusion, the proposed method has shown great potential for the building extraction from HRSI.

• Korean Journal of Remote Sensing
• /
• v.29 no.2
• /
• pp.161-172
• /
• 2013

The construction of hyperspectral test-bed dataset is essential for the effective performance of hyperspectral image for various applications. In this study, we analyzed the technical points for generating of optimal hyperspectral test-bed site for hyperspectral sensors and the efficiency of hyperspectral test-bed site. In this regard regions we analyzed existing construction techniques for generating test-bed site in domestic and foreign, and designed the test-bed site to acquire images from the airborne hyperspectral sensor. To produce a reference data from the image of constructed test-bed site, this study applied vicarious correction as a pre-processing and analyzed its efficiency. The result presented that it was ideal to use tarp for the vicarious correction, but it is possible to use the materials with constant spectral reflectance or with relatively low variance of spectral reflectance. The test-bed data taken in this study can be employed as the reference of domestic and foreign studies for hyperspectral image processing.

• Korean Journal of Remote Sensing
• /
• v.36 no.2_1
• /
• pp.179-197
• /
• 2020

Topographic normalization reduces the terrain effects on reflectance by adjusting the brightness values of the image pixels to be equal if the pixels cover the same land-cover. Topographic effects are induced by the imaging conditions and tend to be large in high mountainousregions. Therefore, image analysis on mountainous terrain such as estimation of wildfire damage assessment requires appropriate topographic normalization techniques to yield accurate image processing results. However, most of the previous studies focused on the evaluation of topographic normalization on satellite images with moderate-low spatial resolution. Thus, the alleviation of topographic effects on multi-temporal high-resolution images was not dealt enough. In this study, the evaluation of terrain normalization was performed for each band to select the optimal technical combinations for rapid and accurate wildfire damage assessment using PlanetScope images. PlanetScope has considerable potential in the disaster management field as it satisfies the rapid image acquisition by providing the 3 m resolution daily image with global coverage. For comparison of topographic normalization techniques, seven widely used methods were employed on both pre-fire and post-fire images. The analysis on bi-temporal images suggests the optimal combination of techniques which can be applied on images with different land-cover composition. Then, the vegetation index was calculated from the images after the topographic normalization with the proposed method. The wildfire damage detection results were obtained by thresholding the index and showed improvementsin detection accuracy for both object-based and pixel-based image analysis. In addition, the burn severity map was constructed to verify the effects oftopographic correction on a continuous distribution of brightness values.

• Progress in Medical Physics
• /
• v.15 no.2
• /
• pp.105-111
• /
• 2004

The parallel plate detector with dielectric film for dosimetry was designed to measure detection characteristic of 6 MV X-ray with medical linear accelerator. PTFE film was inserted into FEP films that are made by two one-side metal coated materials for ion source. The thicknesses of PTFE dielectric film was 100 ${\mu}{\textrm}{m}$ and the thickness of FEP dielectric film was 100 ${\mu}{\textrm}{m}$, respectively. This detector was fixed by two acrylic plate for physical hardness ad geometrical consistency. The geometrical condition for measurement with parallel-plate for detector was below; SSD=100 cm and the 5 cm depth between detector and phantom surface The major parameter of detector characteristics such as zero drift current, leakage current, charge response by applied voltage, reproducibility, linearity, TMR measurement, dose rate effect were measured. The zero drift currents are 8.3 pA and leakage currents are 10 pA. The charge response of applied voltage is showing linearity in 414 voltage. The measurement deviation of reproducibility in this detector is within 1% for dose and the linearity of applied dose shows in this detector. The TMR curves in phantom between this parallel plate detector and reference detector are matched within 3% deviation from maximum dose depth to 7.5 cm depth. It is considered that this dosimetric system is satisfactory for the purpose of the constancy check of the 6 MV x-ray from medical linear accelerator.

• Journal of the Korean Society for information Management
• /
• v.33 no.1
• /
• pp.247-268
• /
• 2016

Although it has been a long subject of study why researchers prefer some cited documents to others, the existing relative researches have had a variety of perspectives on the nature and complexity of the citation behavior and not provided a complete answer to this question. In particular, Korea researchers mainly used statistical analysis of bibliographic information, which has limitations in revealing dynamic and complex cognitive aspects of the citation process. In this study, I investigate the citer perception of citing motives and bibliographic factors through survey and compared the responses according to the researchers' characteristics. After extracting the 22 motivations and 21 factors through the literature analysis and configuring a 5-point Likert scale questions, I conducted a survey in the wat of an e-mail attachment. From the SPSS 22.0, the frequency analysis, t-test, and one-way ANOVA were performed on the 354 valid samples. As a result, it is found that supporting is considered the most important citing motive and social connection, self-citation have little influence. In the case of bibliographic factors, the journal's reputation was recognized the most influential factor and the number of pages and authors was the least. Significant differences in fields of study and research careers were showed in some parts. These results can substantiate earlier studies, determine whether the factors assumed influential in selecting references were intended, and suggest the search point to the specialty library or academic database.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.5
• /
• pp.415-426
• /
• 2015

Solar radiation under a clear sky is a important factor in the process by which meteorological satellite images are converted into solar radiation maps, and the quality of estimations depends on the accuracy of clear sky models. Therefore, it is important to select models appropriate to the purpose of the study and the study area. In this instance, complex models were applied using Linke turbidity, including ESRA, Dumortier, and MODTRAN, in addition to simple models such as Bourges and PdBV, which consider only the solar elevation angles. The presence of cloud was identified using the Communication, Ocean, and Meteorological Satellite and the Meteorological imager (COMS MI), and reference data were then selected. In order to calculate the accuracy of the clear sky models, the concepts of RMSE and MBE were applied. The results show that Bourges and PdBV produced low RMSE values, while PdBV had relatively steady RMSE values. Also, simple models tend to underestimate global solar irradiation during spring and early summer. Conversely, in the winter season, complex methods often overestimate irradiation. In future work, the cause of overestimation and other factors will be analyzed and the clear sky models will be adjusted in order to make them suitable for the Korean Peninsula.